The present invention relates broadly to a sealing construction for providing a fluid seal intermediate a pair of opposed, mating parts or structures, and more particularly to a combination metal and elastomer gasket construction adapted to provide a fluid seal on large or a complex interface surface such as between an oil pan and an engine or chassis in a vehicle.
Sealing gaskets of the type herein involved are employed in a variety of commercial and industrial fluid transport applications for compression between the opposing or faying surfaces of a pair of mating parts or structures to provide a fluid-tight interface sealing thereof. In basic construction, such gaskets are typically are formed of a relatively compressible, annular seal member having a central aperture configured for registration with the corresponding margins of the surfaces.
The seal member optionally may be supported by a generally annular metal or plastic retainer. In such an arrangement, the retainer is stamped or molded, with the seal member being molded-in-place in a groove formed into one or both sides of the retainer, or about the inner and/or outer periphery of the retainer to form an integral gasket structure.
In use, the gasket is clamped between the mating surfaces to effect the compression and deformation of the seal member and to develop a fluid-tight interface with each of the surfaces of the pipe flanges. Typically, the compressive force is supplied using a circumferentially spaced-apart arrangement of bolts or other fastening members, each of which is received through an indexed pair of bores formed within the surfaces. Depending upon the geometry of the gasket, the fastening members also may index through corresponding apertures formed within the seal or retainer member of the gasket.
Particularly for gasket constructions involving metal retainers, it is sometimes impractical to fabricate unitary gaskets. In this regard, the layout of the retainer as a single piece unit requires the use of a metal sheetstock having dimensions at least as large as the largest outer diametric extent of the retainer. For retainers which are of a relatively large size or of a complex geometry, a significant portion of the sheetstock in not utilized for the retainer itself but instead is essentially extraneous material. Although, of course, this material may be utilized elsewhere, it generally is preferred from a cost standpoint to use smaller sheetstock sizes if at all possible.
One approach to this problem has been to fabricate the gasket in a plurality of segments or sections, each of which is mechanically or otherwise interlocked with another segment to form the desired geometry. Representative gaskets of such type are described further in U.S. Pat. Nos. 1,986,465; 2,722,043; 3,738,670; 4,293,135; 4,380,856; 4,572,522; 4,690,413; 5,149,108; 5,149,109; 5,161,808; 5,236,203; 5,513,603; and 5,536,023.
Heretofore, individual seal members were molded onto each of the retainer segments. Such construction, however, necessities the provision of a joint between the seal member of each of the segments. Typically, these joints are provided by the abutment of the ends of each seal member with a corresponding end of the member on the adjacent segment. As each of these joints presents a potential leak path, it would be preferred to eliminate them if the application would permit.
In view of the foregoing, it is apparent that improvements in the manufacture of segmented metal and elastomer gaskets would be well-received by industry. A preferred gasket construction would be economical to manufacture, but also would exhibit reliable sealing performance. Such a gasket additionally would be capable of providing fluid scaling with a minimum of compression set and resultant torque loss.
The present invention is directed to a method for making a gasket construction of a variety which includes a retainer and an integral sealing element molded-in-place on or otherwise attached to the retainer. The method involves stamping or otherwise fabricating the retainer as a series of individual segments, each of which is mechanically or otherwise interlocked with an adjacent segment to form a retainer assembly which may having a generally closed geometry. A sealing element then is molded in a continuous bead onto the retainer assembly. Advantageously, the fabrication of the retainer in individual segments conserves material and otherwise facilitates its construction. However, by molding the sealing element in a continuous bead onto the assembled retainer, joints within the sealing element are eliminated for more assuredly reliable sealing performance.
It is, therefore, a feature of a disclosed embodiment of the invention to provide a method of making a gasket of a variety which includes a generally annular retainer member having an inner and outer diametric extent which define a perimeter of a closed geometric shape, and at least one generally annular seal member formed of an elastomeric material and supported on the retainer member to be compressible intermediate a pair of interface surfaces for providing a fluid-tight seal therebetween. At least a first and a second retainer segment each is provided as extending intermediate a first end and a second end, and as having an inner periphery and an outer periphery. To form the retainer member, the first end of each of the retainer segments is connected to the second end of an adjacent segment such that the inner periphery of each segment defines a portion of the inner diametric extent of the retainer member, with the outer periphery of each segment defining a portion of the outer diametric extent of the retainer member. The seal member then is attached to the retainer member so formed as a continuous ring of elastomeric material which extends along the perimeter of the retainer member.
Advantages of the present invention include a sealing gasket construction which exhibits reliable sealing properties and torque retention with a minimum of compression set. Additional advantages include a gasket construction which is economical to manufacture, and which may be fabricated in complex shapes and large-size geometries. These and other advantages will be readily apparent to those skilled in the art based upon the disclosure contained herein.